| Autor: |
Chaput DL; Biosciences, Geoffrey Pope Building, University of Exeter, Exeter, Devon EX4 4QD, UK., Bass D; Centre for Sustainable Aquaculture Futures, University of Exeter, Exeter, Devon EX4 4QD, UK.; International Centre of Excellence for Aquatic Animal Health, Centre for Environment, Fisheries and Aquaculture Science (Cefas), Weymouth Laboratory, Weymouth, Dorset DT4 8UB, UK., Alam MM; Department of Aquaculture, Bangladesh Agricultural University, Mymensingh-2202, Bangladesh., Hasan NA; Department of Aquaculture, Bangladesh Agricultural University, Mymensingh-2202, Bangladesh., Stentiford GD; Centre for Sustainable Aquaculture Futures, University of Exeter, Exeter, Devon EX4 4QD, UK.; International Centre of Excellence for Aquatic Animal Health, Centre for Environment, Fisheries and Aquaculture Science (Cefas), Weymouth Laboratory, Weymouth, Dorset DT4 8UB, UK., Aerle RV; Centre for Sustainable Aquaculture Futures, University of Exeter, Exeter, Devon EX4 4QD, UK.; International Centre of Excellence for Aquatic Animal Health, Centre for Environment, Fisheries and Aquaculture Science (Cefas), Weymouth Laboratory, Weymouth, Dorset DT4 8UB, UK., Moore K; Exeter Sequencing Service, Geoffrey Pope Building, University of Exeter, Exeter, Devon EX4 4QD, UK., Bignell JP; International Centre of Excellence for Aquatic Animal Health, Centre for Environment, Fisheries and Aquaculture Science (Cefas), Weymouth Laboratory, Weymouth, Dorset DT4 8UB, UK., Haque MM; Department of Aquaculture, Bangladesh Agricultural University, Mymensingh-2202, Bangladesh., Tyler CR; Biosciences, Geoffrey Pope Building, University of Exeter, Exeter, Devon EX4 4QD, UK.; Centre for Sustainable Aquaculture Futures, University of Exeter, Exeter, Devon EX4 4QD, UK. |
| Abstrakt: |
Tilapia lake virus (TiLV), a negative sense RNA virus with a 10 segment genome, is an emerging threat to tilapia aquaculture worldwide, with outbreaks causing over 90% mortality reported on several continents since 2014. Following a severe tilapia mortality event in July 2017, we confirmed the presence of TiLV in Bangladesh and obtained the near-complete genome of this isolate, BD-2017. Phylogenetic analysis of the concatenated 10 segment coding regions placed BD-2017 in a clade with the two isolates from Thailand, separate from the Israeli and South American isolates. However, phylogenetic analysis of individual segments gave conflicting results, sometimes clustering BD-2017 with one of the Israeli isolates, and splitting pairs of isolates from the same region. By comparing patterns of topological difference among segments of quartets of isolates, we showed that TiLV likely has a history of reassortment. Segments 5 and 6, in particular, appear to have undergone a relatively recent reassortment event involving Ecuador isolate EC-2012 and Israel isolate Til-4-2011. The phylogeny of TiLV isolates therefore depends on the segment sequenced. Our findings illustrate the need to exercise caution when using phylogenetic analysis to infer geographic origin and track the movement of TiLV, and we recommend using whole genomes wherever possible. |
